This invention is directed to vibration isolators and is more particularly directed to a new and improved fluidic isolator system in which a liquid and the vapor of the liquid are positioned in the isolator and the liquid is heated or permitted to cool to adjust the relative height of the isolator.
Pneumatic vibration isolators such as shown and described in U.S. Pat. Nos. 3,115,944, 2,956,761 and 2,613,925 and elastomeric-pneumatic vibration isolators such as shown in U.S. Pat. No. 3,836,134 use a compressed gas usually air contained within the isolator to support the static weight of the isolator payload or mechanical payload. These gas filled isolators are generally used to obtain a low mechanical spring stiffness and resulting low vibration system natural frequency.
The relative height of the payload with respect to the base of the isolator or other reference point (generally called the isolator relative height) is a function mainly of the static payload weight and the internal pressure contained within the isolator. At a gas pressure, generally represented by the symbol P.sub.i, the isolator relative height is at the desired value. This height, however, will generally vary by large amounts as payload static weight is varied, and by smaller amounts as temperature and atmospheric pressure change.
In order to overcome the variation of relative isolator height changes with respect to payload weight and other environmental changes, the magnitude of the pressure P.sub.i is varied to maintain a constant relative height. This is generally accomplished by the use of mechanical or electromechanical pneumatic valves to automatically regulate the pressure P.sub.i in order to maintain a constant isolator static height in spite of payload static weight variations and other environmental changes.
While pneumatic valves work quite well, they have the disadvantage of being rather costly. Accordingly, a new and improved isolator regulating system was needed in order to control relative isolator height without the use of a pneumatic valve and pneumatic compressors for air supply.
The present invention provides such an isolation system which does away with the need for a pneumatic valve and compressed air supply.